Compatibility issue: `KaptJavaCompiler` cannot access `JavaCompiler` with Java 21

[igperez-ar]

Description

When building the project using Java 21 with the current Kotlin version, the following error occurs:

superclass access check failed: 
  class org.jetbrains.kotlin.kapt3.base.javac.KaptJavaCompiler (in unnamed module @0x36ee51e2)
  cannot access class com.sun.tools.javac.main.JavaCompiler (in module jdk.compiler) because
  module jdk.compiler does not export com.sun.tools.javac.main to unnamed module @0x36ee51e2
  	at java.base/

Environment

• Java version: 21
• Kotlin version: 1.9.10
• Gradle version: 8.0
• Operating System: MacOS 15.3.1 (24D70)

Steps to Reproduce

1. Set up the project having the SDK set globally with Java 21.
2. Use the specified Kotlin version.
3. Run the build process.

Expected Behavior

The project should build successfully without compatibility issues.

Actual Behavior

The build fails with the superclass access check failed error due to module access restrictions in Java 21.

[igperez-ar]

Update Kotlin and Gradle for Java 21 Compatibility

This issue occurs when using Java 21 with the latest Android Studio setup and the current Kotlin version. The error is caused by an incompatible Kotlin version with Java 21.

The fix involves updating:

1. Kotlin version (compatible with Java 21)
2. Gradle distribution (compatible with the new Kotlin version)

The compatibility information was found on the official Compose Kotlin Releases, and the solution is based on this StackOverflow answer.

Below is the diff to apply:

Index: app/build.gradle.kts
===================================================================
@@ -47,7 +47,7 @@
         buildConfig = true
     }
     composeOptions {
-        kotlinCompilerExtensionVersion = "1.5.3"
+        kotlinCompilerExtensionVersion = "1.5.6"
     }
     packaging {
         resources {

Index: build.gradle.kts
===================================================================
@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     id("com.android.application") version "8.1.2" apply false
-    id("org.jetbrains.kotlin.android") version "1.9.10" apply false
-    id("org.jetbrains.kotlin.jvm") version "1.9.10"
+    id("org.jetbrains.kotlin.android") version "1.9.21" apply false
+    id("org.jetbrains.kotlin.jvm") version "1.9.21"
     id("org.jetbrains.kotlin.plugin.serialization") version "1.9.10"
 }

Index: gradle/wrapper/gradle-wrapper.properties
===================================================================
@@ -1,6 +1,8 @@
 #Sat Nov 04 11:14:56 TRT 2023
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.0-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

Summary of Changes:

• The Kotlin version is updated to 1.9.21 when the issue it's solved.
• The Gradle version is updated to 8.5 to match the required Kotlin version.

Impact:

• Fixes compatibility issues with Java 21.
• Allows new users with the latest Android Studio setup to build the project without errors.